Recovery of high purity 1-butene from refinery or chemical plant cracked C4 streams, such as from a steam cracker or fluid catalytic cracker, requires that 1-butene be separated in high yield and high efficiency from all other species in the feed. Most species can be removed by fractionation. One of the difficulties in recovering linear butenes is that isobutene has a boiling point very close to that of the desired 1-butene. This makes isobutene very difficult to separate by fractionation. In light of this, a common method to remove isobutene from 1-butene feedstock is to convert the isobutene to methyl-t-butyl ether (“MTBE”). However, using MTBE as a gasoline additive is becoming less common, as regulations may phase out such production. Thus, other means for recovering linear butenes is needed.
It has been known to use certain catalysts to dimerize, oligomerize or otherwise convert olefins as in U.S. Pat. No. 3,531,539, U.S. Pat. No. 5,134,241, U.S. Pat. No. 6,518,473, U.S. Pat. No. 7,183,450, U.S. Pat. No. 7,196,238, US 2002/0103406, US 2004/0030212, and US 2007/0213576. Other olefin conversion processes are described in U.S. Pat. No. 4,777,316, U.S. Pat. No. 4,956,514, U.S. Pat. No. 6,111,159, and US 2007/0185359. What is needed is an industrially useful method of isolating and purifying linear butenes from hydrocarbon feeds containing linear butenes and isobutene. An apparatus that could utilize existing facilities designed and/or used for other purposes would be particularly useful.